Oil furnace boiler



Feb. 26, 1935. H, s. WOODRUFF 1,992,794

OIL FURNACE BOILER Filed Jufie 20, 1953 2 Sheets-Sheet 1 Ihvehcoh:

Hehbg S. \A/oodhuffi by W His Attovneg.

Feb. 26, 1935. H, s. WOODRUFF OIL FURNACE BOILER Filed June 20, 1953 2 Sheets-Sheet 2 Henr S. \n/oodruffi Inventor:

His At OFhe Patented Feb. 26, 1935 UNITED STATES PATENT OFFICE on. FURNACE BOILER Henry S. Woodruff, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York This invention relates to boiler furnaces, par-'- ticularly of the welded steel, domestic heating,

ing increased heating capacity and efficiency,

particularly in steam or hot water house heating systems.

Among the more specific objects are to provide a unitary house heating boiler furnace of welded steel construction that afiords a maximum size water-backed combustion chamber and secondary heat absorbing passage with a minimum of material and hence is lightweight and relatively inexpensive but strong and safe and can be easily handled and installed; that requires no special foundation and occupies little floor space; and which still will adequately and efliclently take care of the house and hot water heating requirements of the average home.

The improved boiler furnace of the present invention is particularly adapted for burning oil although other fuels such as gas, powdered coal, or the like may be burned if desired.

The present invention is an improvement upon the boiler furnace construction described and broadly claimed in the copending application of Aldo Macchi, Serial No. 676,106, filed June 16, 1933, and assigned to the assignee of the present invention.

The improved combinations of shells, fire tubes, walls, conduits, chambers, heating coils, flue pans, and the like, whereby the above and other objects are attained, are shown in their preferred forms in the accompanying drawings in which Fig. 1 is a vertical cross sectional view of the improved boiler furnace of the domestic heating type particularly adapted for burning oil; Fig. 2 is a horizontal cross sectional view on the line 2+2 and Fig. 3 is a perspective view showing clearly the eccentric nested arrangement of the inner and outer shells with the fire tubes forming the secondary heat absorbing surfaces in the space provided therebetween.

Referring to the drawings, the outer drum of the improved boiler furnace is formed by the shell 10 which, as shown, is of upright cylindrical shape with flat top and bottom walls or end plates 11 and 12. These end plates preferably are joined to the rims of the shell 10 by welding as indicated by the-fillets in the drawing. An inner casing or shell 13 is nested eccentrically inside of the outer shell 10 and is joined to the bottom end plate 12 thereof preferably by welding as indicated by the fillets. This inner shell 13 also is of cylindrical shape with the flat top wall or end plate 14 thereof in spaced apart relation with the top end plate 11 of the outer shell thus providing a water space over the top and around the sides of the combustion chamber 15 interiorly of the inner shell 13.

The tubular conduit 16 extends between the openings 17 and 18 in the top end plates 11 and 14 thus strengthening and supporting these flat surfaces and also providing a passage into the combustion chamber 15 through which fuel may 10 be fed. As indicated in the drawing, an oil burner atomizing nozzle 19 or any other suitable fuel feeding mechanism may be mounted inside the conduit 16 which is axially alined with the combustion chamber 13 so as to project the fuel 15 centrally therein. In the part of the bottom end plate 12 which is common with the combustion chamber shell 13, an opening 20 is provided in opposing axial alinement with the conduit 16. This opening permits the air nozzle 21 and the 20 combustion air distributing box 22 to be arranged at the bottom of the combustion chamber in opposing relation with the fuel mechanism 19 so that the method of combustion described and broadly claimed in the pending application of 25 Aldo Macchi, Serial No. 505,867, filed December 31, 1930, and assigned to the assignee of the pres! ent invention may be carried out if desired. In case this method of combustion is not to be used, then the fuel may be fed through conduit 16 30 and opening 20 closed up or the fuel and air fed through opening 20 and conduit 16 eliminated.

The bottom portion of the combustion chamber 15 is shown provided with the refractory lining formed by the rows of interlocking blocks 35 23 and the bottom end plate 12 is also covered by the refractory pieces 24.

An exhaust chamber 27 for the products of combustion is formed at the top of the combustion chamber 15 by the casing 28 which extends 4o outwardly from the side of the shell 13 into the enlarged portion of the water chamber formed by the eccentric nesting of the shells with the bottom wall 29 in opposing spaced relation with the bottom end plate 12. This chamber 27 is of 4,5 arcuate or curved shape as shown in Fig. 2 so as to permit the arcuate row of fire tubes 30 to be extended through openings formed in the bottom wall 29 of the exhaust chamber and the bottom end plate 12 and welded thereto. With this con- 50 v To obtain a uniform and even flow of the exhaust gases through all of the fire tubes 30, the

removable baflie 31 is located centrally at the entrance into the exhaust chamber 27.

For the purpose of collecting and conducting in Fig. 2 so as to collect the exhaust gases from the bottom ends of the arcuate row of tubes and is provided with a flanged outlet 34 to which the flue elbow 35 may be attached. As shown, this flue elbow 35 is provided with a pressure release door 36 which is biased by the coil spring 37 to the closed position. I

An auxiliary water chamber 38 is formed by the casing 39 which extends from the side of the outer shell 10 adjacent the top-there0f and opposite the enlarged portion of the water'space between the shells. In this auxiliary water chamber 38, the domestic water heating coil 40 is mounted by means of the clamp fittings 41 and 42. An opening 43 is formed in the bottom wall of the auxiliary chamber 38 .of suflicient size to permit the water coil 40 to pass therethrough. This opening is closed by the removable cover plate 39' towhich the water coil 40 is fastened by the fittings 42. This plate is held in place by the fastening studs 44.v

A portion of the auxiliary water chamber 3 extends downwardly below the normal water level of the boiler and below the level of the exhaust chamber 28 and. the tops of the fire tubes 30 and the chamber communicates with the enlarged water space inside the tank 10 through the openings 45 and 46 which are formed in the side of the outer shell 10 so as to permit free circulation of the wateror steam therethrough.

The outlet 50 of the boiler is provided in the top wall of the auxiliary water chamber 38 and the bolted screw flange 51 is provided for connection to the pipes of a steam, hot water or vapor house heating system. The two screw threaded return openings 52 and 53 are provided in the outer shell 10 adjacent the bottom thereof on either side of the flue pipe 35 so that one or the other or both may be connected to the pipes of the heating system as found most convenient in installing the boiler.

It will be observed that the return pipe openings 52 and 53 are located so as to communicate directly into the enlarged space between the inher and outer shells in which the row of secondary heat absorbing tubes 30 is placed. This insures a maximum circulation of water over these tubes thereby increasing the heating efficiency and capacity of the boiler and reducing the temperature of the products of combustion to the minimum value.

The provision of the auxiliary water chamber 38 also facilitates the circulation of water heated by contact with the tubes 30 by providing an enlarged path around the exhaust chamber 27 which extends from the side of the combustion chamber shell 13. The auxiliary water chamber 38 also materially increases the steam releasing area of the boiler without materially increasing the size of the outer shell 10. This promotes a quiet release of steam without appreciable foaming or priming as the steam bubbles arising from the water-backed surfaces of the secondary heat absorbing tubes 30 and also the sides of the com- Steenstrup, Serial No. 737,947, file bustion chamber shell 13 adjacent thereto have a comparatively free and unrestricted path to the surface of the water by the provision of the auxiliary water chamber 38. A further advantage provided by the increased steam releasing.

area is that the larger ratio of surface area at the water line to volume of water in the boiler tends to reduce the degree of fluctuation of available steam accumulating space under varying operating conditions, since it is evident that a given change in the volume of the water in the boiler will produce a smaller change in water level when the water surface is large in comparison with the volume. The location of the water heating coil within the chamber 38 provides for the maximum interchange of heat from the heated boiler water to the domestic hot water which u circulates inside of 'the coil 40. It will be understood that the flttings 41 and 42 of the hot water heating coil 40 are arranged to be connected to the conventional type of domestic hot water storage tank in the usual'manner.

'While forming no part of the present invention, the oil atomizing nozzle 19 and electric motor driven oil and air pressure unit 54 are shown as of an improved type, which are more fully described and' claimed in the copending appli-' cation of John Eaton and Walter O. Lum, Serial No. 691,320, filed Sept. 28, 1933 and the copending applications of Walter O. Lum, Serial No. 737,063, filed September 26, 1934, a Christian August 1, 1934. These parts as shown are mounted at the top of the boiler furnace and enclosed within the cover 55 along with the ignition transformer 56 and the control mechanism 57.

The unit 54 is connected by the pipe 70 to sup-- ply air under pressure to the atomiz'ing nozzle 19 and is connected to the pipe 71 to supply oil to the nozzle. Low pressure combustion air is supplied from the blower 72 of the unit 54 through the flexible connecting pipe 73 to the nozzle. Part of the air from the blower 72 is supplied to the outlet 74 which connects with the pipe or duct 75 shown in Fig. 2', this duct extending exteriorly of the boiler and into communication with the air box 22 at the bottom of the furnace.

The ignition transformer 56 is connected to energize the spark terminals 76. The oil supply tank is connected to the burner mechanism 54 by means of the pipe 77 and the air is fed into the cover 55 through the casing 78 and also around the-duct 75 in the casing 78a.

The oil burner and control elements are inter- ,connected and arranged to operate as more fully set forth and claimed in the copending application of John Eaton, Serial No. 735,103, flled July 14, 1934, under the control of a room thermostat and various other safety and control switch mechanisms including the safety switch 58 which is shown connected to be operated whenever the pressure release door 36 opens in a manner which need not be further described for an understanding of the present invention.

The boiler furnace of the present invention is preferably provided with a heat insulating covering 60 extending around the sides and over the top thereof. This heat insulating covering is enclosed within an outer metal jacket or covering 61 which is arranged to be fitted around the boiler furnace to provide a pleasing and durable outer cover.

In order to give access into the combustion chamber 15 during installation or repair, the boiler furnace preferably is provided with the cylindrical conduit 67 between the inner and outer shells with the conduit 6'7 welded thereto as indicated by the fillets.

The particular improved construction of the swinging service door 65 is described in detail and claimed in my copending patent application Serial No. 686,713, filed August 25, 1933. Briefly, 'this arra-ngement'is such that the entire door structure may be removed by loosening the securing bolts 68 so as to give access to the combustion chamber 15 for installing the refactory blocks 23, the air nozzle 21, and removable baflle 31 as well as other parts inside of the combustion chamber. However, with the service door mechanism 65 in operating position as shown in the drawing, upon raising the door the inner shutter 69 is also raised so that the condition'of' the flame inside the combustion chamber 15 may be observed through a sight glass. The exact construction and operation of this mechanism as well as the restriction of heat radiation and transfer through the door by the specially formed refractory ring 23a all are fully described and claimed in my pending application noted above.

The boiler furnace, as shown, is provided with an improved form of instrument panel 79, the detailed construction and operation of which are set forth and claimed in my copending application Serial No. 698,121, filed Nov. 15, 1933. It may be noted here, however, that this improved instrument panel 79 is so arranged that for service of the boiler furnace in steam systems, indications of steam pressure and boiler water level are obtained whereas in hot water systems indications of the hydrostatic head or altitude and of the boiler water temperature are obtained.

Various details entering into the boiler furnace construction are shown in the drawing such as the safety fusible plug 80, the four supporting legs 81 which are welded to the bottom end plate 12 and support the boiler furnace the proper distance above the floor line to meet code requirements and also provide the space for the air box 22 and the flue pan32 beneath the boiler furnace. This space is enclosed by the apron 82 thereby providing a dead air pocket which prevents any material loss of heat from the bottom of the boiler furnace even though the bottom end plate 12 is not water-backed.

Installation of the improved boiler furnace is easily accomplished. Since it is of unitary construction and of light weight, it may be easily handled and moved as a unit through doorways and down cellarways or through small passages. It isv a quite simple matter to set the boiler furnace upon its supporting legs 81 and make the necessary connections of the outlet 50 and the return 52 and 53 with the pipes of the house heating system. The flue elbow 35 is then connected to the chimney and the necessary oil and electric connections are made with the oil burner mechanism after the atomizing nozzle, compressor and other parts are mounted on top of the boiler under the cover 55. The domestic hot water heating coil40 is readily connected to the storage tank by means of the fittings 41 and 42.

In operation the heat of combustion is rapidly and effectively extracted from the flame in the combustion chamber by the large area of the water -backed surfaces provided by the sides and top of the combustion chamber shell 13. Additional heat is also transferred to water directly through the water-backed walls of the conduit 16. The products of combustion in passing through the exhaust chamber 27 also give up heat through the water-backed walls of this chamber. The

products of combustion are then divided intoa U number of small streams as they pass through the fire tubes 30 with a relatively large area of water-backed surfaces surrounding each of these streams. Thus with the construction of the present invention a large heating capacity and efiiciency is obtained with a boiler furnace of relatively small size.

The eccentric mounting of the inner shell 13 inside of the outer shell 10 provides the space required for the exhaust chamber 27 and the row of secondary heat absorbing fire tubes 30 with a maximum size of combustion chamber interiorly of the inner shell 13 and the minimum size of outer shell 10. The provision of the auxiliary water chamber 38 not only affords the space for mounting the domestic hot water heating coil 40 but also, as previously pointed out, materially increases the effective water space and eflective steam releasing area in the enlarged portion of the boiler adjacent the exhaust chamber 27 and secondary heat absorbing fire tubes 30 where it is most effective. The location of the flue pan 32 outside of the bottom end plate 12 so as to cover the ends of the flre tubes 30 which extend through this end plate and conduct the products of combustion to the flue permits the maximum length for the secondary heat absorbing tubes 30 to be obtained. Also the arranging of the bottom wall of the exhaust chamber 28 in opposing parallel relationship with the bottom end plate 12 materially facilitates the in sertion and welding of the ends of the tubes between the two walls. Also this construction together with the removable bafiie 31 permits the fire tubes 30 to be cleaned by removing the service door 65 and inserting a cleaning brush or chain through the exhaust chamber 28 into the tubes 30. The dirt is easily removed by detaching the fiue elbow 35 from the fiue pan 32 or, if desired, the entire fiue pan 32 may be removed. The location of the boiler outlet 50 on top of the auxiliary water chamber 38 and particularly over the top of the domestic hot water heating coil 40 permits the top portion of the chamber 38 to act as a steam and water separating chamber and thereby reduces the water content of the steam delivered to the house heating system and further permits the upward withdrawal of steam from the boiler without interfering with the burner and control equipment mounted on top of the boiler proper.

What I claim as new and desire to secure by Letters Patent in the United States is:

1. In a boiler furnace, the combination of an upright tubular shell having end plates closing the top and bottom thereof, a second smaller dimensioned upright tubular shell having an end plate closing the top thereof, said second shell being nested within said first shell and joined to the bottom end plate thereof to form a combustion chamber interiorly of said first shell and waterbacked on the sides and top, means providing a fuel passage into the combustion chamber including a tubular conduit extending vertically between the top end plates of said shells and joined to the same around openings provided therein, an air distributionbox detachably secured beneath said bottom end plate in alignment with said first mentioned openings, air supply means located on top of the outer one of said shells and having duct means extending externally of said outer shell for conducting air to said air distribution box, means providing a secondary heat exchange 'pass including a plurality of fire tubes in communication with the upper end of the combination chamber and extending through the space between the shells to openings provided insaid bottom endplate, means for exhausting combustion products from said fire tubes including a flue pan detachably secured beneath said bottom end plate in communication'with the lower ends of the fire tubes, and supporting means secured beneath said bottom end plate for spacing the same above a floor structure to provide room for said air distribution box and said flue pan.

2. In a steam boiler furnace, the combination of a pair of eccentrically nested upright tubular shells having separate top end plates closing the respective upper ends thereof and a single bottom end plate common to and closing the bottom ends thereof, the inner of said shells. being of "smaller dimensions than the outer of saidshells said top walls to provide for the introduction of fuel into said inner shell, means for discharging air upwardly through an opening-in said bottom plate into said innershell to support combustion therein, means providing a combustion gas exhaust chamber including a casing protruding outwardly from said inner shell adjacent the top "thereof and located in the enlarged space pro-- vided'by the eccentric nesting of the shells, a plurality of fire tubes extending from openings in the bottom wall of said casing through said enlarged space to openings in said bottom end wall, means providing a supplementary water and steam accumulation space including a second casing protruding'outwardly from said outer shell adjacent the top thereof and in opposed relation to said first casing, said second c asing having a portion thereof extending below the level of the tops of said fire tubes, an auxiliary heating coil disposed in said second casing and having detachable connections therefor located in the walls of said second casing, a detachable bottom wall for said casing to provide for the removal of said coil, nd means providing a steam outlet located in the top wall of said second casing.

3. In a steam boiler furnace, the combination of a pair of nested upright tubular shells having separate top end plates closing the respective upper ends thereof and a single bottom end plate common to and closing the bottom ends thereof, the inner of said shells being of smaller dimensions than the outer of said shells and providing a combustion chamber waterbacked on sides and top, a tubular conduit extending vertically between'said top end walls to provide a fuel delivery passage into the combustion chamber interior of the inner shell, a plurality of fire tubes in communication with the' combustion chamber at the upper end thereof and extending between said shells to openings provided in'said bottom end wall, means for supplying air to the combustion chamber including air' supply means mounted on top said outer shell and connected externally of said outer shell to discharge air upwardly into the combustion chamber through an opening provided in said bottom end wall,

the top thereof, the lower portion of said casing extending downwardly into opposed spacedproximity to the upper ends of said fire tubes to pro-- vide additional steam releasing surface for the water heated by said fire tubes, and means providing a steam outlet extending upwardly from the top of said casing.

4. In a steam boiler furnace the combination of an upright tubular shell having end plates closing the top and bottom thereof, a second smaller dimensioned upright tubular shell having an end plate closing the top thereof, said second shell being eccentrically nested within said first shell and joined to the bottom end plate thereof to form a combustion chamber having a water and steam accumulation space thereabove and a water space therearound, a tubular conduit extending vertically between the top end plates of said shells coaxially of the inner one of said shells to provide a passage for the introduction of fuel into the combustion chamber, an air inlet opening located in said bottom end plate coaxiallyofsaid conduit, means for delivering air to the combustion chamber including air'distribution means arranged to discharge air upwardly through said opening and air supply means located on top the outer one of said shells with duct means extending externally of said outer shell between said supply means and said distribution means, means providing a combustion gas exhaust chamber including a casing protruding outwardly from said inner shell into the enlarged portion of the space between the eccentrically nested shells and in communication with the combustion chamber adjacent the top thereof, fire-tubes extending vertically from openings provided in the bottom wall of said casing to openings provided in said bottom end plate, means for exhausting gases from the combustion chamber through said exhaust casing and said fire tubes including a flue pan located beneath said bottom end plate, means providing an auxiliary water and steam accumulation chamber including a second casing protruding outwardly from said outer shell adjacent the top thereof, a portion of said second casing being located in opposed spaced proximity to said first casing and extending below the level of the upper'ends of said fire tubes to facilitate the collection of steam rising from the outer surfaces of said fire tubes, an auxiliary hot water heating coil located within said second casing and having connections secured in the walls of the second casing, and connection means secured in the top of said second casing above said coil to provide for the drawing off of steam from the boiler.

HENRY S. WOODRUFF. 

